Motor-control system.



J. F. MOTZ.

MOTOR CONTROL SYSTEM.

APPLICATION FILED JULY21', 191s.

Patented Dec. 29, 1914.

. controlled by the push button 13.

Jason. it notes, o's'rrrtrsnunon, runnstnvanie.

BIGTQB-CONTBOL SYSTEM.

Application filed July 21, 1913.

To whom it may concern:

it known that l, JACOB F. Mora, a

- izen of the United States, residing at urgh, in the county of Allegheny and State of Pennsylvania, have invented a new a d useful lslctor-Control System, of which the fOllO'WlIl f isa specification.

invention relates to motor-control systems, particularly to those in which magnetically-operated switches are used to reguate the resistances in the motor circuit.

More particularly, it relates to systems in which the same restistance controlling switches are used in starting the motor when onnect-ed to a suitable source of supply and a stopping; the motor by dynamic braking. or the switches controlling the resistances, l prefer to use those having operating windings energized by current in the motor circuit.

In the accompanying drawing, which is a diagrammatic representation embodying my invention, the motor is shown with the arma sure A. and the field winding F. The system is connected to a source of supply by means of the switch S. For closing the motor circuit to start the motor, I use'the switch M, which is magnetically operated and controlled by means of the push buttons B and 13'. For connecting the motor in the dynamic braking circuit I use the magnetically operated switch D,"whi ih is The interlocking bar K is used to prevent the simultaneous closure of the switches M and D. The resistances R, R and R are controlled by the magietically-operated switches S, "5 and S, which have their operating windit i i ngs C, (P, and C arranged to be connected in theniotor circuit. I prefer to use for these switches the type of switch described in Eastwoods Patent 1,040,292, which has the peculiar characteristic of remaining open it the currentin the operating winding is above a predetermined value, and closing its contacts, when the current in the Winding is reduced. The switch 9 is provided with a holding winding H, which is a fine wire winding adapted to be connected across the source of supply to hold the switch closed; his terminal of this winding is connected to the push buttons l3 and B while the Specification of Letters Eatent.

1 A. i :7;- p n 1 Patten .ee

Serial no. "(some other terminal is connected to a part iii i? switch and the winding becomes energized upon the closure of the switch.

In starting the motor, the motor is cennected to the source or" supply through the switch M, the circuit including the \\i;lt'llilif C of the switch S and all the starting rcsistance. The startingresistance is then automatically cut out by the closure of the resistance switches, the motor being thus brought up to speed.

To stop the motor the switch hi is opened and the switch I) closed, whereupon the motor is connected in a closed or dyna? ic braking circuit, including the winding C of the switch S" and the portions R and R of the starting resistance. These portions of the resistance are then cut out automatically by the closure of the switches S and S and'the motor is quickly brought to rest by the-current flowing in the dynamic braking circuit, which is maintained at a high value by the cutting out of the resistances therein.

The operation of the control system is as follows: When the switch S is closed, the field of the motor is energized from positive through the wires 1 and '2, the fieldF, and the wire 12 to the negative. The motor is started by the operator pressing the normally open push button B. The winding;

m of switch M is then energized throughthe circuit from positive through the wires 1 and l, the contacts of the push button BJ the wire 5, the winding m, and the i} to the negative. The switch M thereupon closes and is then held closed by its'winding which is new energized from the positive through tnecontacts of the switch Til, the wire 7, the contacts of the push button B-, the wires 8 and 5, the winding m, and the wire 6 to negative. T he operator can now release the push button B and the switch M will remain closed through the circuit including the push bu ton which has just been described. Upon the closure of theswitch M, the motor circuit is as l lows: from positive through the swit the motor armature A, the wire 11, winding C, the resistanceslt, and the wire 12 to the negative. nowstarts and may he ion by the progressiveclosure of the switches S, S and S each switch being prevented from closure until the current in its winding has diminished to such a value as will be safe for cutting out the neXt section of resistance. The switch S in closing cuts out the resistance R and energizes the winding C of the switch S Likewise the switch. S in closing cuts out the resistance R and energizes the winding C of the switch S When the switch S closes, current goes through the wire. 13, the contacts of the switch S and the wire 12, instead of through the wire 11, as previously traced. The switch S in closing cuts out the resistance R and deenergizes the windings 0,-

C and C The switches S and S drop open, but the switch S remains closed since it is held closed by its winding H, which is energized upon closure of the contacts of the switch S To-stop the motor, the operator can open the normally closed push button B which will cause the switch M to open and disconnect themotor from the source of supply, allowing the motor to come to rest. The opening of the switch B also deenergizes the winding H, causing the switch S to open. If a quick stop is desired, the operator closesthe normally open push button B, which can be accomplished by a continued movement of the push button B The push button B in, closing energizes the winding d of-switch I) through the following circuit: from positive through the wires 1 and 4, the contacts of the push button B the wire 10, the winding cl, and the wire 6 to thenegative. The switch D now closes and connects the motor in a dynamic braking circuit which is as follows: from the left-hand. brush of the armature A,

through the switch D, the wire 14, the resistances R and R, the winding C of the switch S, and the wire 11 to the righthand brush of the armature. Current fiowing in this circuit causes the winding C to close switch S when the current is re duced to the propervalue. This cuts out. the resistance R- and energizes the winding C of the switch S The cutting out ofthe resistance R causes the motor current to increase, thereby increasing the re tardation of the motor. \Vhen this cur rent is reduced to the proper amount, switch S5 closes, thereby cutting out the resistance It and energizing the winding C of the switch S This causes a further increase of current and further retardation of the motor. Upon the closure of the switch S the resistance R is connected in parallel with the windings G, C and C and the resistance of the circuit is now of a very low value, which willbring the motor quickly to rest. The circuit of the holding winding H is openedupon the opening/oi,

, the said switch is opened.

the push button B so that no current flows in this winding while the motor is being slowed down. Then the motor comes to rest, current ceases to flow in the motor circuit, and all the switches will open their contacts, their windings being deenergized. To start the motor again, the operator releases the push buttons B and B allowing them to assume their normal positions as shown in the drawing, and closes the push button B. The operation will then be as previously described.

When the dynamic braking circuit is closed, the current in the windings C, C and C is in a reverse direction to that when the motor is being started. This assists in locking the switches open when the current is too high, but does not interfere with the closure of the switches when the current in the winding diminishes to the proper value.

It will be readily understood by those skilled in the artthat other arrangements of parts can be made than those here shown without departing from the spirit of my invention.

I claim.

1. In a motor control system, a motor armature, a switch, a resistance controlled thereby, a winding for closing the switch,

means for connecting the armature and the windingto a source of supply to start the motor, and means for connecting the armature and the winding in a closed'circuit to stop the motor.

2. In a motor control system, a series of switch contacts, resistance controlled thereby, windings for operating the contacts, a motor armature, means for connecting the contacts, the resistance, and the switch windings to a source of supply in series with the motor armature to start the motor, for disconnecting the said contacts, resistance, and switch windings from the source, and for connecting them in a closed circuit, with the armature to slow down the motor.

3. In a motor control system, a motorarmature, a resistance, switch contacts for controlling the resistance, a winding for operating the contacts energized by curthe winding, and the resistance all in series,

. and for connecting the armature, the winding, and the resistance in a closed circuit.

4. In an electric controller, a circuit, a resistance for controlling the circuit, switch contacts therefor, a .winding for operating the contacts connected in the circuit, a switch for connecting the winding and the resistance to a source of supply. and means for connecting thewinding and the rcsistancefin a closed circuit when '5. In an electric controller, a circuit, a resistance for controllin the circuit. switch Signed at Pit sburgh, Pa., this 19 'of July, A. D. 1913.

JACOB F. MOTZ.

day

Witnesses:

ALICE E. DUFF, ELVA STANIEK. 

